21543621120 has 720 divisors, whose sum is σ = 88743695040. Its totient is φ = 4731125760.

The previous prime is 21543621119. The next prime is 21543621247. The reversal of 21543621120 is 2112634512.

21543621120 is a `hidden beast` number, since 2 + 1 + 543 + 6 + 2 + 112 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (720).

It is a super-2 number, since 2×21543621120² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 154990011 + ... + 154990149.

It is an arithmetic number, because the mean of its divisors is an integer number (123255132).

Almost surely, 2^21543621120 is an apocalyptic number.

21543621120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21543621120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44371847520).

21543621120 is an abundant number, since it is smaller than the sum of its proper divisors (67200073920).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21543621120 is a wasteful number, since it uses less digits than its factorization.

21543621120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 237 (or 187 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The spelling of 21543621120 in words is "twenty-one billion, five hundred forty-three million, six hundred twenty-one thousand, one hundred twenty".